Grinding attachment for lawn-mowers



March G. HAINES, SR

GRINDING ATTACHMENT FOR LAWN MOWERS Filed Jan. 28, 1931 "'llllmlllliATTORNEY Patented iMar. 22 1932 UNITED STATES PATENT OFFICE LAWRENCE G.HAIN'IES, SR., 01 GLASSBORO, NEW JERSEY GRINDING ATTACHMENT FORLAWN-MOWERS.

Application filed ma 28,1931. Serial No. 511,665. 1

. This. invention relates to sharpening de-' vlces for lawn mowers andanalogous machines and has more especial relation to improvements uponthe grinding attachment disclosed in myPatent No. 893,164, issuedJuly14, 1908.

While the structure disclosed in my aforesaid patent has in practicegiven excellent results, long and continued use thereof haslo'demonstrated the need of certain additions point of maximumefficiency.

and changes to enhance its usefulness to the As an example, the angular,resllient plate supporting the abrading material in use has loose.

the tendency to buckle intermediate its length so that in rotation ofthe mower blades true contact is not always present. Again,

practice dictates that the angular brackets supporting thearcuate armsfrequently jar Further, these arcuate arms because of their open endspermitdislodgment of the butterfly nuts employed in connectiontherewith. -;Still further, removal when desired of theabrading carryingelement is not as convenient as maybe.

" The leading object of the present invention, therefore, may be saidtobe the overcoming of these objectionable features and to provide anarrangement, connectlon, and

combination of'parts for enhancing the com mercial valueof the grindingattachmen embodying the invention. I

With this and other objects in view, the invention consists of the novelconstruction hereinafter described and finally claimed.

The nature, characteristic features and scope of the invention will. bemore fully understood from the following description taken, inconnection'with the accompanying drawings forming part hereof, and. inwhich:

a Fig. 1 is a cross sectional: view of a lawnmower having appliedthereto the attachment embodying: the invention I Fig. Qisa-vievv inperspective of the attachment, embodying the nvention, de-

tached; V

Fig. ;3 is a fragmentary view 1n plan of certain of the parts shown inFig. 2;

Fig. 4* is a view principally in cross-section of the attachment shownin Fig. 2

*that the various instrumentalities ofwhich my invention consists can.be variously arranged and organized and that my invention is not limitedto the precise arrangement and organization of the instrumentatlities asherein shown and described. 7

Referring to the drawings in'detail, there is disclosed a lawn-mowerhaving driving wheels 2, rotary blades 8, a l'Ollel'd, and a handle 5,all of which parts may be of any desired construction. Having adjustablerelation with the frame 6 which supports the roller 4 are arcuate arms7, slotted "as at 8 throughout the entire length of each arm. The endsof the arms, however, are closed at each end as indicated by thereference nu meral 9. These arms 7 after proper adjustment may besecured .to place and permitted tofremain upon the lawn-mower duringfunctioningthereof. Arranged to be attached tow and detached from thesearms 7 is arectangular sharpening device capable of adjustment withrespecttothearms 7 in a manner to be hereinafter more particularlydescribed.

The rectangular sharpening device comprises v a resilient metallicelongated plate 10 having extended upwardly therefrom at its rear theflange 11 to provide a relatively L-shaped is turned over upon itself toprovide. a reinforcing rib 12. .The upper edge of the flange 'll'isturned over upon itself as at 13 to provide a reinforcing rib. Both theplate 10 and the flange 11 at their opposed ends are bent over uponthemselves to provide reinstructurey The plate lOat its forward endforcing ribs 14. These reinforcing ribs'add strength and relativerigidity to the sharpening device. Fitted to the bottom of the plate 10and over the rib 12 is a sheet of f abrading material 15,11sually ofemery cloth.

In practice the abrading material is usually glued to the plate 10.Fitted to the rear of the flange 11 is a thin metal bar 16. This bar issecured centrally of the flange 11 by means of a screw 17 and a nut 18,see Fig. l.

7 At this point of attachment the screw 17 and nut 18 are utilized forsecuring in position a leaf spring 19, the free end of which is causedto engage beneath the reinforcing rib 12. The purpose of this leafspring 19 is to insure relative rigidity of the plate 10, thus tendingto maintain the plate 10 closely adjacent the blades 3 in theirrotation. In order to provide additional stability to the plate 10,additional leaf springs 20 are provided one upon either side of the leafspring 18, as best seen in Fig.2. Having slidable relation with respectto the bar 16 is a pair of oppositely disposed angular brackets 21, eachslotted as at 22. The inner ends of each of these brackets is closed asat 24 and the opposite end of each of these brackets terminates in aforked open-ended portion 25. In practice screws 26 and nuts 28 areemployed for securing the slotted brackets 21 with respect to theflanged portion of the plate 10. As plainly shown in Fig. 3,substantially U-shaped clamps 29 are fitted over the brackets 21 and thescrews 26 caused to pass through these clamps and through the slottedportion of the brackets 21 and through both the flange 11 and the leaf srings 20, whereby with the tightening of tile nuts 28 the angularbrackets 21 may be secured in adjustable position. The function of thebrackets 21 is that of accommodating securing of the attachment as awhole to various sizes of lawn-mowers. By this structure shown in myaforesaid patent, these brackets frequently became loose, and I havediscovered that by employing the U-shaped clamps 29 this defect isovercome. In practice the brackets 21 may be permanently attached, ifdesired, to the arms 7 of the lawn-' mower by means of butter-fly nuts30. However, to facilitate ready removal of the attachment as a wholefrom a lawn-mower, I havefound it convenient to leave the ends of thebrackets 21 open as at 25 as before described, whereby it is merelynecessary to unloosen the butter-fly nuts 30 and withdraw the bracketsfrom the arms 21 without actuall removing the butter-fly nuts.

. The construction disclosed in Fig. 6 is similar in all respects tothat previously described with the exception that the plate holding theabrading material is curved upon its underside as at 31.

The above described attachment is adjusted upon a lawn-mower when it isdesired to sharpen the rotary blades and is so arranged that as theblades revolve in a backward or reverse movement to that ordinarily usedin the cutting of grass, the heel of each knife comes in contact withthe abrading surface of the attachment to effect a keen cutting edge forthe blades. By reason of the special resilient features of the combinedplate and leaf springs the blades of the lawn-mower contact with theabrading material with just suflicient pressure to effect efiicient sharening without causing the cutting parts 0 the blades to be unduly worn.In practice it has been demonstrated that very good results may beobtained by sharpening the blades of a lawn-mower by revolvin I theblades backwardly, as fully set fort in my aforesaid patent.

I am aware that the invention may be embodied in other specific formswithout departing from the spirit or essential attributes thereof, and Itherefore desire the present embodiment to be considered in all respectsas illustrative and not restrictive, reference being had to the appendedclaims rather than to the foregoing description to indicate the scope ofthe invention.

What I claim is:

1. A sharpening attachment for a lawnmower, comprising a relativelyresilient plate carrying a sheet of abraiding material, said platehaving a flange at its rear, the edges of said plate and flange bothlongitudinally and laterally considered being folded over to provide areinforcement, a leaf spring secured 1 between the longitudinalreinforcement portions of said flange and plate at each end thereof, anda second leaf spring similarly secured intermediate said first mentionedleaf springs for relatively stiffening the central portion of saidplate.

2. A sharpening attachment for a lawn mower, comprising a relativelyresilient plate carrying a sheet of abrading material, said plate havinga flange at its rear, the edges of.

said plate and flange both lon itudinally and laterally considered beingfol ed over. to provide a reinforcement, a leaf spring secured betweenthe longitudinal reinforcement portions-of said flange and thereof, anda second lea s ring similarly secured intermediate said rst mentionedleaf springs for relatively stiffening the'central ortion of said plate,and angular slotted brac rets adjustably mounted at each end of u saidflange, the inner ends of said brackets being closed to said slots buthaving their outer ends open to said slots.

3. A sharpening attachment for a lawn mower, comprising a relativelyresilient plate carrying a sheet of abrading material, said plate havinga'fiange at its rear, the edges of said plate and flan e bothlongitudinally and laterally considere being folded overto provide areinforcement, a leaf spring secured between the longitudinalreinforcement portions of saidflange and plate at each end thereof, asecond leaf 5 ring similarly secured intermediate said rst mentionedleaf springs for relatively stiffening the central portion of saidplate, and pairs of substanlate at each end.

tially U-shaped clamps for engaging over that portion of each of saidbrackets which parallels saidflange. c

4. A sharpening attachment for a lawn mower, comprising a relativelyresilient plate carrying a sheet of abraiding material, said platehaving a flange at its rear, the edges of said plate and flange bothlongitudinally and laterally considered being folded over to provide areinforcement, a leaf spring secured betweenthe longitudinalreinforcement por- I tions of said flange and plate at each end thereof,a second leaf spring similarly secured intermediate said first mentionedleaf springs for relatively stiffening the central portion of saidplate, and screws and bolts for securing said clamps to place,said'screws and bolts serving to secure at least some of said leafsprings to place.

5. A sharpening attachment for a lawnmower, comprising a relativelyresilient plate I carrying a sheet of abrading material, said platehaving a flange at its rear, the edges of said plate and flange bothlongitudinally and laterally considered being folded-over to provide areinforcement, a leaf spring secured between the longitudinalreinforcement portions of said flange and plate at each end thereof, asecond leaf spring similarly secured intermediate said first mentionedleaf springs for relatively stiflening the central portion of saidplate, and an arcuate slotted arm carried by each of said brackets, bothends of each of said arms being closed to said slots. V

LAWRENCE Gr. HAINES, SR

